Some facilities include back-up components and systems to provide back-up power to electrical devices in the event of a failure of components or systems in a primary power system. In some facilities, each primary power system may have its own back-up system that is fully redundant at all levels of the power system. For example, in a data center having multiple server rooms, each server room may have its own primary power system and back-up power system. The back-up system for each server room may have a switchboard, uninterruptible power supply, and floor power distribution unit (PDU) that mirrors a corresponding switchboard, uninterruptible power supply, and floor power distribution unit in the primary power system for that server room. In other facilities, multiple primary power systems may be supported by a shared back-up system. For example, in a data center having multiple server rooms, each server room may have its own primary power system, but may share a reserve power system with one or more other ones of the server rooms.
Some facilities with primary power systems and back-up power systems include automatic transfer switches to switch between the primary and back-up power systems in case of a loss of power in one of the power systems. Such automatic transfer switches may include mechanical components, such as a mechanical switches, that require periodic testing and maintenance, thus adding to costs of operation. Also, some mechanical automatic transfer switches may fail to switchover or may be delayed in switching during a loss of power event thus adversely affecting operation of electrical devices, such as computer systems, receiving electrical power via the automatic transfer switches.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include,” “including,” and “includes” mean including, but not limited to.